i was skeptical about all this claying stuff so i first washed and then used a light paint cleaner (einsZett) on my car. used the paint cleaner first just to make sure that the clay bar wasn't doing the same thing the cleaner would do. i then simply ran my fingers lightly across the surfaces (no baggies or similar) to find the telltale junk left in the top layer. i took the clay bar to those areas and sure enough, it removed the contaminants and left the surface smooth as silk!

while one might have used a more abrasive cleaner to rid the paint of the contaminants, the clay bar provided quick results with a lot less work. i'm sold! i'd still recommend using a light cleaner first just to save your clay from picking up all of the stuff the cleaner removes.